Yeah, to secure a military vehicle in a lot, they use a regular padlock. Guarantee a key is lost every quarter, and the unit in charge has to go out and cut it to get access to their own vehicle. This guy came in with bolt cutters, and then used the combat lock on the door he entered in. The only possible way a policeman without heavy ordnance got in with boltcutter, and the thief used a combat lock, was if there was another door that was padlocked closed, but not combat locked.
Tldr; yeah, you can still steal a military vehicle if you can sneak into an army base with a pair of boltcutters. It sure as shit won't be loaded, and if you pick the wrong one it might not even start up because they all breakdown regularly, and aren't clearly marked as such.